Solid-state NMR has seen a tremendous growth in recent years and certain techniques have become fairly routine. Other solid- state NMR techniques are very demanding of the spectrometer. In the last few years, instrumentation which is powerful, sophisticated, and reasonably easy to use has become commercially available. This proposal is for partial funding of such an instrument capable of obtaining spectra on a variety of solid samples, as well as large liquid samples. Problems under investigation by the prime user group are 1) host molecules that complex and catalyze, 2) reactive molecules and novel materials, 3) guest dynamics and reactions in solid state host-guest complexes, 4) energetics of gastric proton transport, 5) molecular basis of membrane excitation, and 6) chemical equilibria in the solid state: electronic transformations of iron porphyrin complexes.